The present invention relates to a bridge composed of at least one bridge element comprising a basic bridge body having sloped end faces that terminate at mid height of the basic bridge body. The end faces are provided with a hinge connection at which a folding ramp is mounted to be pivotal in such a way that it rests on the sloped surface or--if folded down and fixed to the basic bridge body by means of a locking arrangement--it forms a common access ramp together with the sloped surface of the basic bridge body.
Such bridges are known as floating bridges (disclosed, for example, in German Offenlegungsschrift 19 63 393) as well as "fixed bridges" that are deployable on solid ground (disclosed, for example, in published European Patent Application 0,407,274 to which corresponds U.S. Pat. No. 5,033,145). Depending on the width of the obstacle to be spanned, the bridges may be composed of a single bridge element or a plurality of identical bridge elements. In a bridge composed of a single bridge element, both folding ramps are folded down and locked to the basic bridge body. In a bridge composed of two bridge elements, the folding ramps are folded down at their ends facing away from one another and are locked to the basic bridge body while at the mutually facing ends the folding ramps rest on the sloped surfaces of the basic bridge bodies. In that state they form an essentially vertical end with the basic bridge bodies. Both such ends of the bridge elements are locked at the bottom to the basic bridge bodies and, if necessary, at the top to the folding ramps in order to form a load-carrying bridge. For bridges composed of more than two bridge elements, both folding ramps of the bridge elements disposed between the outer bridge elements lie on the basic bridge body and are thus in an upfolded position. In each instance--independently of the number of bridge elements involved--the bridge elements are all identical and are universally employable as a center section, a ramp section or as an element that in itself forms a bridge.
The basic bridge bodies form a roadway on their top surface and the folding ramps form a roadway on their top and bottom surfaces. If the folding ramps are placed on the sloped surfaces of the basic bridge bodies, the basic bridge body and the folding ramp together form a continuous roadway. The basic bridge body and the folding ramps may extend over the entire width of the roadway, or they may constitute only the width of one track (lane) and may be connected in a known manner by means of transverse supports.
While the German patent document 19 63 393 discloses no structural details, in the bridge elements disclosed in European Patent Application 0,407,274 the locking arrangement is composed of a hook coupling which, however, is able to transmit only tensile forces. For transmitting transverse forces, additional convex and corresponding concave shaped elements are provided which, however, represent additional weight thus reducing the load carrying capability of the bridge. It is another disadvantage of this prior art construction that if the bridge has been soiled by use, the hook couplings may not operate reliably and thus increased expenditures are involved in verifying the operational reliability of the bridge to be deployed.
In a bridge center section in which the folding ramps rest on the basic bridge body, as in the bridge disclosed in the earlier-noted European patent application, the pressure forces acting on the folding ramp in the longitudinal direction of the bridge are transmitted to the basic bridge body essentially by way of a hinge connection. In the downfolded state for forming a ramp section or an individual bridge, the hinge joint lies at the height of the roadway so that it is subjected to wear from heavy vehicles, particularly track-laying vehicles, that drive over it.